Hi, long time lurker…I may have posted once or twice here in years past.
I am seeing lines as pictured below on both Winchester brass, bought as new empty brass and loaded and fired two times, and S&B brass which is pictured, bought as new ammo, fired and then reloaded and fired again. Or in other words in both cases, twice fired. I’ve seen pictures on the net of brass separated at this point, and found one discarded case at the range which had separated here. Is this what I’m looking at, near failures? I see this on about 1/4 to 1/3 of my brass, to varying degrees. Fired cases compared to full length resized cases show difference in shoulder length of .002" to.003" in other words I don’t think head space is excessive. Fired in Rem 700. Of course the simple answer is don’t reuse any brass that has these marks, but I wonder what’s the cause given that I see it on so much of my brass. Any advice is surely appreciated.
I agree with Clint and the chamber reamer left a ring in the chamber and it transfers to the case. Many times a metal chip gets stuck to the reamer and leaves a ring in the chamber.
You can check the case and chamber with a bent paper clip and feel for a dip or ridge.
A finish reamer might remove this ring in the chamber, if the rifle is new I would contact Remington and have them fix it at no cost.
Both Remington and Winchester are hollow shells of what they once were, and quality control is governed by the share holders.
Below .308 cases fired in a new Savage bolt action
Below on the far right is a .303 British case that was fired twice in a generous Enfield chamber. This case has stretched but has not separated showing what the brass looks like before a separation.
Below my $100.00 bent paper clip a RCBS case mastering gauge I use to check for case stretching and thinning. I collected Enfield rifles and they could be very hard on cases if not fire formed properly.
Below at max Enfield military headspace of .074 and a rim thickness of .058 you could have .016 head clearance. And a big difference between that and .002 to .003 shoulder bump.
Thanks for the replies. I can neither feel nor see anything in the chamber but it is a long reach and it may be difficult to detect something thta’s not real obvious. Someone asked what case trimmer I use. It’s a Lyman and it grips the case by the rim. There is no contact at that point.
I’m still being cautious here. I think I will find one case with the most pronounced mark and cut it just to see the inside. Want to be sure I’m not heading for something like this picture (not mine):
If you are going to check for stretching and thinning it is best to cut the case in half lengthwise.
Below I collected British .303 Enfield rifles that were noted for their over sized chambers. This Winchester case was fired in a No.4 Enfield that was within American SAAMI headspace limits meaning betweem .064 and .067, and max military headspace is .074. This case still stretched and thinned .009 on the first firing, but this was due to thin rims and thinner commercial cases.
I agree with markm and my guess is the marks are still being caused by the chamber.
Below when the case is held at the right angle you will see the machine marks transfered to the outside of the case. The case below was not a total case head separation and no harm was done to the chamber or myself. Normally the gas leakage is vented away from the shooters face and not noticed until the case is inspected.
Below “click…bang” (hang fire) surplus Pakistani .303 ammo and opening the bolt before the bang. This blew the magazine out the bottom of the rifle and luckily only left brown stains in the shooters underwear.
Post your findings. I’m curious now. I really don’t think there’ll be anything in the brass. And for what it’s worth… a case separation is an inconvenience, not a safety issue.
